In an example method for redundant multicast trees with fast recovery, a protocol independent multicast (PIM) backup designated router (BDR) can receive a request from a host to join a multicast group associated with a source; send to a next hop a PIM join message identifying an address of the PIM BDR and identifying the PIM join message as a backup PIM join; receive, from a PIM router along a path to/from the source, a unicast message sent to the address which identifies a second address associated with the PIM router; store the second address and a route associated with the unicast message; in response to a designated router migration trigger, set to blocking a backup multicast tree state associated with the source and multicast group; and send, to the PIM router, a unicast message including instructions to set to blocking a backup multicast tree state at the PIM router.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method comprising: receiving, by a protocol independent multicast (PIM) backup designated router (BDR), a request from a host device to join a multicast group associated with a source of multicast traffic; generating, by the PIM BDR in response to the request, a PIM join message that comprises attributes identifying a first address of the PIM BDR and indicating that the PIM join message is a backup PIM join from a backup designated router; sending, by the PIM BDR, the PIM join message towards the source of multicast traffic to a next hop between the PIM BDR and the source of multicast traffic; receiving, by the PIM BDR, from a PIM router located along a path between the PIM BDR and the source of multicast traffic, a first unicast message sent to the first address, the first unicast message identifying a second address associated with the PIM router; storing, by the PIM BDR, the second address associated with the PIM router and a route used in delivering the first unicast message to the PIM BDR; in response to a designated router migration triggering event, changing a first instance of a backup multicast tree state at the PIM BDR from blocking to forwarding, the backup multicast tree state being associated with the source of multicast traffic and the multicast group; and sending, by the PIM BDR to the PIM router through the route used in delivering the first unicast message to the PIM BDR, a second unicast message comprising an instruction to change a second instance of the backup multicast tree state at the PIM router from blocking to forwarding.
This invention relates to multicast routing in network environments, specifically addressing redundancy and failover mechanisms in Protocol Independent Multicast (PIM) networks. The problem solved is ensuring seamless transition of multicast traffic when a designated router (DR) fails, minimizing service disruption. A backup designated router (BDR) receives a join request from a host device to join a multicast group associated with a source of multicast traffic. The BDR generates a PIM join message containing its own address and an indicator that it is a backup PIM join. This message is sent toward the source via a next-hop router. The BDR then receives a unicast message from a PIM router along the path, which includes the router's address and the route used to deliver the message. The BDR stores this information. Upon a DR migration event (e.g., failure), the BDR transitions its local backup multicast tree state from blocking to forwarding. It then sends a unicast message to the PIM router, instructing it to similarly transition its backup state to forwarding. This ensures that multicast traffic continues flowing without interruption, leveraging pre-established backup paths and state synchronization. The solution enhances reliability in multicast networks by pre-configuring backup routes and states, enabling rapid failover.
2. The method of claim 1 , wherein changing the first instance of the backup multicast tree state from blocking to forwarding and sending the second unicast message comprises changing a role of the PIM BDR from backup DR to active PIM DR.
A method for improving network reliability in multicast routing involves managing Protocol Independent Multicast (PIM) Designated Router (DR) roles to enhance failover mechanisms. The method addresses the problem of network disruptions caused by single points of failure in multicast routing, particularly when the primary PIM DR fails. In a network with multiple routers, the method ensures seamless transition of multicast traffic by dynamically adjusting the roles of backup routers. When a failure occurs, the backup PIM DR (Backup Designated Router, BDR) is promoted to the active PIM DR role. This transition involves changing the state of the backup multicast tree from a blocking state to a forwarding state, allowing the backup router to take over multicast traffic forwarding. Additionally, a second unicast message is sent to notify other network devices of the role change, ensuring synchronization and preventing traffic loss. The method enhances network resilience by reducing downtime during DR failures and maintaining continuous multicast traffic delivery.
3. The method of claim 2 , further comprising sending, by the active PIM DR to the next hop, one or more PIM join messages comprising active PIM joins, the one or more PIM join messages being sent at one or more intervals.
This invention relates to network routing, specifically to optimizing multicast traffic forwarding in a Protocol Independent Multicast (PIM) network. The problem addressed is inefficient multicast traffic distribution, where redundant or unnecessary traffic is sent to network nodes that do not require it, leading to wasted bandwidth and processing resources. The invention describes a method for managing multicast traffic in a PIM network, where a designated router (DR) acts as an active PIM DR for a multicast group. The active PIM DR is responsible for forwarding multicast traffic to downstream routers. To improve efficiency, the active PIM DR sends one or more PIM join messages to the next hop router at specified intervals. These PIM join messages include active PIM joins, which are requests to receive multicast traffic for a particular group. By sending these messages periodically, the active PIM DR ensures that the multicast traffic is only forwarded to routers that have explicitly requested it, reducing unnecessary traffic distribution. The method also involves the active PIM DR receiving PIM join messages from other routers in the network and processing these messages to determine which multicast groups should be forwarded. The active PIM DR then forwards the multicast traffic only to the next hop routers that have sent valid PIM join messages, ensuring that traffic is only sent to nodes that require it. This approach minimizes bandwidth usage and optimizes network performance by preventing redundant multicast traffic from being sent to unnecessary nodes.
4. The method of claim 1 , wherein sending the PIM join message to the next hop comprises sending the PIM join message towards at least one of the source of multicast traffic and a merge point for an active multicast tree associated with the multicast group and a backup multicast tree associated with the multicast group.
This invention relates to multicast routing in network systems, specifically improving reliability and redundancy in Protocol Independent Multicast (PIM) networks. The problem addressed is ensuring continuous multicast traffic delivery even when primary paths fail, by maintaining backup multicast trees that can seamlessly take over. The method involves sending a PIM join message to establish a multicast path. The key improvement is that the join message is directed not only toward the source of multicast traffic but also toward a merge point that connects both an active multicast tree and a backup multicast tree for the same multicast group. This ensures that if the primary path fails, the backup tree is already in place and can immediately provide traffic without interruption. The merge point acts as a convergence point where the active and backup trees intersect, allowing quick failover. By sending the join message toward either the source or the merge point, the system ensures that the backup tree is properly established and ready to handle traffic if needed. This approach enhances network resilience by reducing downtime during failures and improving overall reliability of multicast services. The solution is particularly useful in environments where uninterrupted multicast traffic delivery is critical, such as live streaming, financial data distribution, or real-time communication systems.
5. The method of claim 1 , wherein the PIM router comprises at least one of a first hop router (FHR) connected to the source of multicast traffic, a merge point between an active multicast tree associated with the multicast group and a backup multicast tree associated with the multicast group, and a rendezvous point (RP) router configured as a root of at least one of the active multicast tree and the backup multicast tree, the PIM router being downstream from the source of the multicast traffic and upstream from the PIM BDR.
This invention relates to multicast routing in network systems, specifically addressing redundancy and reliability in Protocol Independent Multicast (PIM) networks. The problem solved is ensuring continuous multicast traffic delivery even when primary paths fail, by implementing a backup mechanism that maintains an alternative multicast tree structure. The system involves a PIM router that serves as a critical node in the multicast distribution network. This router can function in multiple roles: as a first hop router (FHR) directly connected to the multicast traffic source, as a merge point between an active multicast tree and a backup multicast tree for the same multicast group, or as a rendezvous point (RP) router acting as the root of either the active or backup multicast tree. The PIM router is positioned downstream from the multicast source but upstream from a PIM Backup Designated Router (BDR), which handles failover operations. By strategically placing the PIM router in these roles, the system ensures that multicast traffic can be rerouted through the backup tree if the active path fails, maintaining service continuity. The backup tree is pre-established and synchronized with the active tree, allowing seamless switchover without traffic interruption. This approach enhances network resilience by providing redundant paths for multicast data distribution.
6. The method of claim 5 , wherein the PIM router comprises the merge point between the active multicast tree and the backup multicast tree, the PIM router being located between the PIM BDR and a different PIM router comprising at least one of the FHR and the RP router.
This invention relates to multicast routing in network systems, specifically addressing redundancy and failover mechanisms in Protocol Independent Multicast (PIM) networks. The problem solved is ensuring seamless continuity of multicast data streams when primary paths fail, particularly in scenarios involving PIM Designated Routers (DRs) and Backup Designated Routers (BDRs). The invention describes a method for managing multicast traffic using a PIM router that acts as a merge point between an active multicast tree and a backup multicast tree. This PIM router is positioned between the PIM BDR and another PIM router, which may include either the First Hop Router (FHR) or the Rendezvous Point (RP) router. The merge point ensures that multicast data can be dynamically rerouted from the active tree to the backup tree in the event of a failure, minimizing disruption. The PIM BDR is responsible for maintaining the backup tree, while the FHR or RP router handles the initial multicast source or distribution point. The merge point router facilitates the transition between these trees, ensuring that multicast traffic continues to flow without significant delays or packet loss. This approach enhances network resilience by providing a clear, structured failover mechanism for multicast routing.
7. The method of claim 6 , further comprising: receiving, by the PIM router comprising the merge point, the PIM join message from the PIM BDR; determining that the PIM router has previously received an active PIM join associated with the multicast group and has an active multicast tree state associated with the multicast group, the active PIM join being from an active PIM designated router (DR), and the active multicast tree state comprising the active multicast tree; setting the second instance of the backup multicast tree state at the PIM router to a blocking state, wherein the second instance of the backup multicast tree state comprises the backup multicast tree; and sending, by the PIM router, the first unicast message to the first address identified in the PIM join message from the PIM BDR, the first unicast message indicating that the PIM router is the merge point between the active multicast tree and the backup multicast tree.
This invention relates to multicast routing in a network, specifically to a method for managing multicast trees in a Protocol Independent Multicast (PIM) network. The problem addressed is ensuring seamless failover between an active multicast tree and a backup multicast tree in a PIM network, particularly when a new PIM join message is received from a PIM Backup Designated Router (BDR). The method involves a PIM router acting as a merge point between an active multicast tree and a backup multicast tree. When the PIM router receives a PIM join message from the PIM BDR, it checks whether it has previously received an active PIM join for the same multicast group and whether it has an active multicast tree state for that group. If so, the router sets the backup multicast tree state to a blocking state, preventing traffic from flowing through the backup tree. The router then sends a unicast message to the address specified in the PIM BDR's join message, indicating that it is the merge point between the active and backup multicast trees. This ensures that the PIM BDR is aware of the merge point, allowing for efficient failover if the active tree fails. The method improves network reliability by maintaining synchronization between the active and backup multicast trees.
8. The method of claim 5 , further comprising: receiving, by a different PIM router, an active PIM join associated with a second host device and the multicast group, wherein the different PIM router comprises a new merge point for the backup multicast tree and the active multicast tree, wherein the different PIM router is located along a path between the source of the multicast traffic and both the second host device and the PIM BDR; determining that the different PIM router has previously received the backup PIM join and has a third instance of the backup multicast tree state associated with the multicast group, the third instance of the backup multicast tree state comprising the backup multicast tree; setting the third instance of the backup multicast tree state to a blocking state; sending, by the different PIM router, a third unicast message to the first address identified in the PIM join message from the PIM BDR, the third unicast message indicating that the different PIM router is the new merge point for the active multicast tree and the backup multicast tree; and sending, by the different PIM router, a copy of the active PIM join to the PIM router, the copy of the active PIM join identifying a second address associated with the different PIM router and identifying the different PIM router as the new merge point.
This invention relates to multicast routing in network environments, specifically improving redundancy and failover mechanisms in Protocol Independent Multicast (PIM) networks. The problem addressed involves ensuring seamless failover between active and backup multicast trees when a new merge point is introduced along the path between a multicast source and host devices. The method involves a different PIM router acting as a new merge point for both the active and backup multicast trees. When this router receives an active PIM join from a second host device, it checks if it has previously received a backup PIM join and maintains a backup multicast tree state. If so, it sets this state to a blocking state to prevent duplicate traffic. The router then sends a unicast message to the original backup designated router (BDR), identifying itself as the new merge point. Additionally, it forwards a copy of the active PIM join to the original PIM router, specifying its own address and confirming its role as the new merge point. This ensures that the backup tree remains synchronized with the active tree while maintaining proper traffic flow and redundancy. The solution enhances network resilience by dynamically adjusting multicast paths without disrupting service.
9. The method of claim 8 , further comprising: in response to receiving the PIM join message sent by the PIM BDR, storing, by the PIM router, the second instance of the backup multicast tree state and a unicast address associated with a designated destination for unicast communications relating to at least one of the backup multicast tree and the active multicast tree, the unicast address comprising the first address of the PIM BDR; in response to receiving the active PIM join, updating the unicast address to the second address of the different PIM router; and updating the second instance of the backup multicast tree state at the PIM router based on the active PIM join.
This invention relates to multicast routing in network protocols, specifically addressing the management of backup multicast trees in Protocol Independent Multicast (PIM) networks. The problem solved involves efficiently maintaining and transitioning between active and backup multicast trees to ensure reliable data delivery in the event of primary router failures. The method involves a PIM router that receives a PIM join message from a PIM Backup Designated Router (BDR). In response, the PIM router stores a backup multicast tree state and a unicast address associated with a designated destination for unicast communications related to either the backup or active multicast tree. The unicast address initially includes the first address of the PIM BDR. Upon receiving an active PIM join message, the PIM router updates the unicast address to a second address of a different PIM router, replacing the BDR's address. Additionally, the PIM router updates the stored backup multicast tree state based on the active PIM join message. This ensures seamless transition and synchronization between active and backup multicast trees, maintaining network reliability during router failures or transitions. The method enhances fault tolerance and reduces service disruption in multicast networks.
10. The method of claim 1 , further comprising: receiving, by the next hop, the PIM join message from the PIM BDR; in response to receiving the PIM join message, determining that the next hop does not have multicast tree state associated with the multicast group and the source of the multicast traffic; instantiating the multicast tree state at the next hop; storing, by the next hop, the first address associated with the PIM BDR as a unicast address associated with the PIM BDR; and sending, by the next hop, a copy of the PIM join message towards the PIM router, the copy of the PIM join message identifying the first address associated with the PIM BDR.
This invention relates to multicast routing in network environments, specifically addressing the establishment and management of multicast tree states in Protocol Independent Multicast (PIM) networks. The problem solved involves efficiently handling PIM join messages when a next-hop router lacks existing multicast tree state information for a given multicast group and source. When a next-hop router receives a PIM join message from a PIM Backup Designated Router (BDR), it checks whether it has an existing multicast tree state for the specified multicast group and source. If no such state exists, the next-hop router instantiates the multicast tree state. The router then stores the BDR's first address as a unicast address associated with the BDR. Finally, the next-hop router forwards a copy of the PIM join message toward the PIM router, ensuring the join message includes the BDR's first address. This process ensures proper multicast traffic forwarding while maintaining accurate routing state information. The invention optimizes multicast routing by dynamically establishing necessary states and preserving BDR address information for reliable message propagation.
11. The method of claim 1 , wherein the designated router migration triggering event comprises at least one of a failure of a link between the PIM router and a PIM designated router (DR) associated with the multicast group and the source of the multicast traffic, a failure associated with the PIM DR, and a failure associated with one or more interfaces of one or more PIM routers located along an active path between the PIM DR and the PIM router.
This invention relates to network routing, specifically to methods for triggering router migration in a Protocol Independent Multicast (PIM) network. The problem addressed is ensuring reliable multicast traffic delivery by detecting and responding to failures in the network path between a PIM router and a designated router (DR) for a multicast group. The invention provides a method for detecting specific failure conditions that trigger a migration of the designated router role to another router in the network. The method monitors for three types of failure events. First, it detects failures in the link between the PIM router and the current PIM DR, which may disrupt multicast traffic flow. Second, it identifies failures associated with the PIM DR itself, such as hardware or software malfunctions that impair its ability to forward multicast traffic. Third, it detects failures in one or more interfaces of routers along the active path between the PIM DR and the PIM router, which could also disrupt traffic delivery. When any of these failure events occur, the system triggers a migration process to select a new designated router, ensuring continued multicast traffic delivery. This approach improves network resilience by proactively responding to path or router failures in multicast networks.
12. A system comprising: a protocol independent multicast (PIM) backup designated router (BDR) comprising one or more processors and at least one computer-readable storage medium having stored therein instructions which, when executed by the one or more processors, cause the PIM BDR to: receive a request from a host device to join a multicast group associated with a source of multicast traffic; generate, by the PIM BDR in response to the request, a PIM join message that comprises attributes identifying a first address of the PIM BDR and indicating that the PIM join message is a backup PIM join from a backup designated router; send the PIM join message towards the source of multicast traffic to a next hop between the PIM BDR and the source of the multicast traffic; receive, from a PIM router located along a path between the PIM BDR and the source of the multicast traffic, a first unicast message sent to the first address identified in the PIM join message, the first unicast message identifying a second address associated with the PIM router; store the second address associated with the PIM router and a route used in delivering the first unicast message to the PIM BDR; in response to a designated router migration triggering event, change a first instance of a backup multicast tree state at the PIM BDR from blocking to forwarding, the backup multicast tree state being associated with the source of the multicast traffic and the multicast group; and send, by the PIM BDR to the PIM router through the route used in delivering the first unicast message to the PIM BDR, a second unicast message comprising an instruction to change a second instance of the backup multicast tree state at the PIM router from blocking to forwarding.
A system for improving multicast traffic resilience in network routing involves a Protocol Independent Multicast (PIM) backup designated router (BDR) that enhances failover capabilities. The BDR includes processors and storage with instructions to manage multicast group joins and state transitions. When a host device requests to join a multicast group, the BDR generates a PIM join message containing its own address and a flag indicating it is a backup request. This message is sent toward the multicast source, propagating through intermediate PIM routers. The BDR receives a unicast response from a PIM router along the path, storing the router's address and the route used for delivery. Upon a designated router migration event, the BDR transitions its local backup multicast tree state from blocking to forwarding for the relevant source and group. It then sends a unicast message to the stored PIM router address, instructing it to similarly transition its backup state. This ensures seamless traffic redirection during failover, maintaining multicast service continuity. The system addresses the problem of multicast service disruption during router failures by pre-configuring backup paths and states, reducing recovery time and improving network reliability.
13. The system of claim 12 , wherein changing the first instance of the backup multicast tree state from blocking to forwarding and sending the second unicast message comprises designating the PIM BDR as an active PIM designated router (DR) and changing a role of the PIM BDR from backup designated router to active designated router, and wherein the at least one computer-readable storage medium stores additional instructions which, when executed by the one or more processors, cause the PIM BDR acting as the active PIM DR to: send, to the next hop, one or more PIM join messages comprising active PIM joins, the one or more PIM join messages being sent at one or more intervals.
This invention relates to network routing protocols, specifically Protocol Independent Multicast (PIM) for efficient data distribution in multicast networks. The problem addressed is ensuring seamless failover and redundancy in multicast routing when a primary designated router (DR) fails, minimizing service disruption. The system involves a backup designated router (BDR) that monitors the primary DR. Upon detecting a failure, the BDR transitions from a blocking state to an active forwarding state, taking over the DR role. This transition includes sending unicast messages to notify network nodes of the change. The BDR, now acting as the active DR, sends PIM join messages at regular intervals to maintain multicast group memberships and ensure continuous data flow. The system uses computer-readable storage media to store and execute these instructions, enabling automated and rapid failover without manual intervention. The solution improves network resilience by dynamically reconfiguring multicast paths during failures, reducing downtime and ensuring uninterrupted multicast traffic delivery. The BDR's proactive role ensures minimal disruption, as it preemptively adjusts routing states and sends periodic join messages to sustain multicast connectivity. This approach is particularly valuable in large-scale networks where multicast services must remain highly available.
14. The system of claim 12 , wherein the PIM router comprises a merge point between an active multicast tree associated with the multicast group and a backup multicast tree associated with the multicast group, the PIM router being located between the PIM BDR and a different PIM router comprising at least one of a first hop router (FHR) connected to the source of the multicast traffic and a rendezvous point (RP) router configured as a root of at least one of the active multicast tree and the backup multicast tree.
A system for multicast routing in a network includes a Protocol Independent Multicast (PIM) router that serves as a merge point between an active multicast tree and a backup multicast tree for a multicast group. The PIM router is positioned between a PIM Backup Designated Router (BDR) and another PIM router, which may function as either a first hop router (FHR) connected to the source of multicast traffic or a rendezvous point (RP) router acting as the root of the multicast trees. The active multicast tree is used for primary multicast traffic distribution, while the backup multicast tree provides redundancy in case of failures. The PIM router facilitates seamless switching between the active and backup trees to ensure continuous multicast traffic delivery. This system enhances network reliability by maintaining redundant paths for multicast traffic, reducing downtime during failures. The PIM BDR monitors the active tree and triggers a failover to the backup tree if necessary, ensuring minimal disruption to multicast services. The system is particularly useful in large-scale networks where multicast traffic must be delivered reliably across multiple routers.
15. The system of claim 14 , further comprising the PIM router, the PIM router comprising one or more additional processors and at least one additional computer-readable storage medium storing instructions which, when executed by the one or more additional processors, cause the PIM router to: receive the PIM join message from the PIM BDR; determine that the PIM router has previously received an active PIM join associated with the multicast group and has active multicast tree state associated with the multicast group, the active PIM join being from an active PIM designated router (DR), and the active multicast tree state comprising the active multicast tree; set the second instance of the backup multicast tree state to a blocking state, wherein the second instance of the backup multicast tree state comprises the backup multicast tree; and send the first unicast message to the first address identified in the PIM join message from the PIM BDR, the first unicast message indicating that the PIM router is the merge point between the active multicast tree and the backup multicast tree.
This invention relates to multicast routing in network systems, specifically addressing redundancy and failover mechanisms in Protocol Independent Multicast (PIM) networks. The problem solved involves ensuring seamless transition between active and backup multicast trees when a designated router (DR) fails, minimizing service disruption. The system includes a PIM backup designated router (BDR) that sends a PIM join message to establish a backup multicast tree. A PIM router, distinct from the BDR, receives this message and checks if it has previously received an active PIM join for the same multicast group from an active DR. If so, the PIM router confirms it has an active multicast tree state, including the active multicast tree. The PIM router then sets the backup multicast tree state to a blocking state, preventing traffic from flowing through the backup tree until needed. The PIM router sends a unicast message to the BDR, identifying itself as the merge point between the active and backup multicast trees. This ensures the backup tree is ready to take over if the active DR fails, maintaining network reliability. The system enhances redundancy by coordinating between active and backup states while preventing unnecessary traffic duplication.
16. The system of claim 14 , further comprising a different PIM router, the different PIM router comprising one or more additional processors and at least one additional computer-readable storage medium storing instructions which, when executed by the one or more additional processors, cause the different PIM router to: receive an active PIM join associated with a second host device and the multicast group, wherein the different PIM router comprises a new merge point for the backup multicast tree and the active multicast tree, wherein the different PIM router is located along a path between the source of the multicast traffic and both the second host device and the PIM BDR; determine that the different PIM router has previously received the backup PIM join and has a third instance of the backup multicast tree state associated with the multicast group, the third instance of the backup multicast tree state comprising the backup multicast tree; set the third instance of the backup multicast tree state to a blocking state; send a third unicast message to the first address identified in the PIM join message from the PIM BDR, the third unicast message indicating that the different PIM router is the new merge point for the active multicast tree and the backup multicast tree; and send a copy of the active PIM join to the PIM router, the copy of the active PIM join identifying a second address associated with the different PIM router and identifying the different PIM router as the new merge point.
This invention relates to a system for managing multicast traffic in a network, specifically addressing redundancy and failover in multicast routing. The system includes a Protocol Independent Multicast (PIM) router that acts as a backup designated router (PIM BDR) for a multicast group. The PIM BDR maintains a backup multicast tree state to ensure continuous multicast traffic delivery if the primary multicast tree fails. The system also includes a primary PIM router that manages an active multicast tree for the multicast group, ensuring traffic reaches host devices subscribed to the multicast group. The system further includes a different PIM router that acts as a new merge point for both the backup and active multicast trees. This router receives an active PIM join from a second host device and detects that it has previously received a backup PIM join, indicating it already has a backup multicast tree state. The router then sets this backup state to a blocking state to prevent redundant traffic. It sends a unicast message to the PIM BDR, identifying itself as the new merge point, and forwards a copy of the active PIM join to the primary PIM router, updating the network topology to reflect the new merge point. This ensures efficient and redundant multicast traffic distribution while minimizing unnecessary traffic.
17. The system of claim 16 , further comprising the PIM router, the PIM router comprising at least one processor and at least one other computer-readable storage medium storing instructions which, when executed by the at least one processor, cause the PIM router to: in response to receiving the PIM join message sent by the PIM BDR, store the second instance of the backup multicast tree state and a unicast address associated with a destination for unicast communications relating to at least one of the backup multicast tree and the active multicast tree, the unicast address comprising the first address of the PIM BDR; in response to receiving the active PIM join, update the unicast address to the second address of the different PIM router; and update the second instance of the backup multicast tree state at the PIM router based on the active PIM join.
This invention relates to multicast routing in network systems, specifically improving reliability and failover mechanisms in Protocol Independent Multicast (PIM) networks. The problem addressed is ensuring seamless transition between active and backup multicast trees when a designated router (DR) fails, minimizing service disruption. The system includes a PIM backup designated router (PIM BDR) and a PIM router. The PIM BDR sends a PIM join message to establish a backup multicast tree. The PIM router, upon receiving this message, stores a backup multicast tree state and a unicast address associated with the PIM BDR. This unicast address is used for communications related to either the backup or active multicast tree. When the PIM router receives an active PIM join message, it updates the stored unicast address to reflect the address of a different PIM router, indicating a transition to a new active state. The PIM router also updates the backup multicast tree state based on this active PIM join, ensuring synchronization between the active and backup states. This mechanism allows for rapid failover and maintains consistent multicast routing information across the network.
18. A non-transitory computer-readable storage medium comprising: instructions stored therein which, when executed by one or more processors, cause the one or more processors to: receive, at a protocol independent multicast (PIM) backup designated router (BDR), a request from a host device to join a multicast group associated with a source of multicast traffic; generate, by the PIM BDR in response to the request, a PIM join message that comprises attributes identifying a first address of the PIM BDR and indicating that the PIM join message is a backup PIM join from a backup designated router; send, by the PIM BDR, the PIM join message towards the source of multicast traffic to a next hop between the PIM BDR and the source of the multicast traffic; receive, by the PIM BDR, from a PIM router located along a path between the PIM BDR and the source of the multicast traffic, a first unicast message sent to the first address identified in the PIM join message, the first unicast message identifying a second address associated with the PIM router; store, by the PIM BDR, the second address associated with the PIM router and a route used in delivering the first unicast message to the PIM BDR; in response to a designated router migration triggering event, change a first instance of a backup multicast tree state at the PIM BDR from blocking to forwarding, the backup multicast tree state being associated with the source of the multicast traffic and the multicast group; and send, by the PIM BDR to the PIM router through the route used in delivering the first unicast message to the PIM BDR, a second unicast message comprising an instruction to change a second instance of the backup multicast tree state at the PIM router from blocking to forwarding.
This invention relates to multicast routing in computer networks, specifically improving reliability in Protocol Independent Multicast (PIM) networks by enhancing backup designated router (BDR) functionality. The problem addressed is ensuring seamless failover in multicast traffic distribution when a primary designated router (DR) fails, minimizing service disruption. The system involves a PIM BDR that receives a join request from a host device to join a multicast group associated with a multicast traffic source. The BDR generates a PIM join message containing its own address and a flag indicating it is a backup join. This message is sent toward the source, propagating through intermediate PIM routers. When a PIM router along the path receives the join, it sends a unicast message to the BDR's address, identifying its own address and the route taken. The BDR stores this information, including the router's address and the delivery route. Upon a DR migration event (e.g., primary DR failure), the BDR transitions its local backup multicast tree state from blocking to forwarding. It then sends a unicast message to the stored router address, instructing it to similarly transition its backup state to forwarding. This ensures the multicast traffic path is quickly reestablished without manual intervention, maintaining service continuity. The solution improves network resilience by pre-configuring backup paths and automating state transitions during failover.
19. The non-transitory computer-readable storage medium of claim 18 , wherein changing the first instance of the backup multicast tree state from blocking to forwarding and sending the second unicast message comprises changing a role of the PIM BDR from backup DR to active PIM DR, wherein the designated router migration triggering event comprises at least one of a failure of a link between the PIM router and a PIM designated router (DR) associated with the multicast group and the source of the multicast traffic, a failure associated with the PIM DR, and a failure associated with one or more interfaces of one or more PIM routers located along an active path between the PIM DR and the PIM router.
This invention relates to network routing, specifically to protocols for handling multicast traffic in a network, such as Protocol Independent Multicast (PIM). The problem addressed is ensuring seamless and reliable multicast traffic delivery when a designated router (DR) fails or when network conditions change, which can disrupt multicast group communication. The solution involves a backup multicast tree state mechanism that allows a backup designated router (BDR) to quickly transition to an active role when a failure occurs. The system includes a PIM router that monitors the state of a multicast group and its associated DR. If a failure event occurs—such as a link failure between the PIM router and the DR, a DR failure, or an interface failure along the active path—the PIM router changes the backup multicast tree state from blocking to forwarding. This transition involves promoting the PIM BDR to the active PIM DR role, ensuring continuous multicast traffic delivery without service interruption. The system also sends a second unicast message to notify other network components of the role change, maintaining synchronization across the network. This approach improves network resilience by minimizing downtime during DR failures or path disruptions.
20. The non-transitory computer-readable storage medium of claim 18 , wherein the PIM router comprises a merge point between an active multicast tree associated with the multicast group and a backup multicast tree associated with the multicast group, the PIM router being located between the PIM BDR and a different PIM router comprising at least one of a first hop router (FHR) connected to the source of the multicast traffic and a rendezvous point (RP) router configured as a root of at least one of the active multicast tree and the backup multicast tree, the non-transitory computer-readable storage medium storing additional instructions which, when executed by the one or more processors, cause the one or more processors to: receive, by the PIM BDR and from a different PIM router, an active PIM join associated with a second host device and the multicast group, wherein the different PIM router comprises a new merge point for the backup multicast tree and the active multicast tree, wherein the different PIM router is located along a path between the source of the multicast traffic and both the second host device and the PIM BDR, the active PIM join identifying a second address associated with the different PIM router and identifying the different PIM router as the new merge point.
This invention relates to multicast routing in computer networks, specifically improving reliability and redundancy in Protocol Independent Multicast (PIM) networks. The problem addressed is ensuring continuous multicast traffic delivery when primary paths fail, particularly in scenarios where a designated backup router (PIM BDR) must seamlessly take over multicast forwarding without service disruption. The solution involves a PIM router acting as a merge point between an active multicast tree and a backup multicast tree for the same multicast group. This router is positioned between the PIM BDR and another PIM router, which could be either a first-hop router (FHR) connected to the multicast traffic source or a rendezvous point (RP) router serving as the root of the multicast trees. The system includes instructions for the PIM BDR to receive an active PIM join message from a different PIM router, which becomes a new merge point for both the backup and active multicast trees. This different PIM router lies along the path between the multicast source and both a second host device and the PIM BDR. The active PIM join message identifies the address of this new merge point router and designates it as the new merge point, enabling dynamic reconfiguration of multicast paths to maintain service continuity during failures. This approach enhances network resilience by allowing backup paths to be pre-established and quickly activated when needed.
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February 28, 2019
April 5, 2022
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